I picked up a 7111 at a swap meet, it is a lot taller than stock. Will the stock 84 Hurst/Olds dual snorkel air cleaner fit under the hood with a 4160? I was thinking of getting a 2711 for the little 307 and saving the RPM for a 350. The QJet is rusted solid and the EGR plumbing is missing. Also I see they offer exhaust crossover plugs # 2733. It rarely gets cold here in Texas, how much of a performance boost do you get on an Olds engine plugging the crossover? Thanks Jackson

 

Forget the 307 as far as performance. It's decent, but limitations in the bore size. The entire engine was designed for maximum fuel and emissions efficiency.

The 350, better yet a 403, is FAR and away a better build base and fits just as nicely in an 84 H/O. With even the mods you hope to do, your computer will have to go anyway. So build a strong 350 or 403 and you'll be much happier.

Pull the original 307, intact, and stash it in the corner of your garage. If you ever sell the H/O down the road, or if someone is looking for an earlier VIN 9 engine with 5A heads and flat tappet cam, you can save the day.

Just suggestions. Do what you wish. But the hood clearance isn't that great on the Cutlass for tall manifolds and taller carbs. The air cleaner will most likely hit with an RPM, and be way too much for the 307 anyway. The 7111 is 2" taller than the 2711. And that H/O hood is unique to the H/O. It has special corner braces underneath for the extra weight of the plastic "scoop" (it's heavier than it looks) so you probably shouldn't go hacking on that special hood. So if you do yank the 307 for a bigger engine, take the hood off and stash it too. Get a low-rise fiberglass cowl hood or something to clear the carb and whatever air cleaner you run.

 

A stock style air cleaner won't fit, I tried it on my 88 Cutlass. What I like about my 70 Cutlass S with the factory raised hood, the RPM and dual snorkel fit with ease. I am even adding a square to spreadbore 3/4" spacer to help the kickdown clear the EFI rails. The crossover plugs add no real performance benefit but help keep heat off the manifold and potentionally cracking it. They need a bunch of grinding and or cutting to fit the plugs in the head, I just did a set. The later heads do hsve larger ctossover, so less needs removed. As said, put in the 350 and get something like the better scoop angle VFN W25 style hood.